Part of the installation of OS X Lion and later is the creation of a hidden recovery volume. You can use this recovery volume to start your Mac up and perform emergency services, such as running Disk Utility to repair a drive, browsing the web to find information on a problem you're having, or downloading a necessary update or two. You can even use the recovery volume to re-install OS X Lion or later, although this involves a full download of the OS X installer.
On the surface, the OS X recovery volume seems like a good idea, but as I have noted before, it has a couple of fundamental flaws. The most glaring problem is that the recovery volume is created on your startup drive. If the startup drive has hardware-based issues, it's conceivable that the recovery volume won't be accessible. That can pretty much put a damper on the whole idea of having an emergency recovery volume.
The second issue is that the OS X installation process can run into problems when trying to create the recovery volume. This is especially true for those Mac users who don't use a straightforward drive setup. Many individuals who use RAID arrays for their startup volume have reported that the installer couldn't create the recovery volume at all.
Recently, Apple came to its senses and released a new utility, the OS X Recovery Disk Assistant, which can create a recovery volume on any external hard drive or flash drive. This lets you place the recovery volume almost anywhere you want it.
Unfortunately, there's a little problem with this approach, too. The OS X Recovery Disk Assistant creates a new recovery volume by cloning the existing recovery volume. If your OS X installation was unable to create the original recovery volume, this new utility from Apple is of little use.
The second issue is that for some reason Apple decided that the OS X Recovery Disk Assistant should only create recovery volumes on external drives. If you have a second internal drive, which is certainly possible on many of the Macs Apple sells, including the Mac Pro, iMac, and Mac mini, you won’t be able to use it as a destination for your recovery volume.
Create Your Own OS X Lion Recovery HD on Any Drive
Despite these flaws, it's still a good idea to have a recovery volume beyond the one initially created during the OS X Lion installation. With that in mind, let's find out how to use the Recovery Disk Assistant.
OS X Recovery Disk Assistant - What You Need
Before we get into the step-by-step guide to using the OS X Recovery Disk Assistant, it's important to take a moment to make sure you have everything you need.
What You Need to Use the OS X Recovery Disk Assistant
A copy of the OS X Recovery Disk Assistant. That's a pretty easy requirement to fulfill; the Recovery Disk Assistant is available from the Apple web site.
A working OS X Recovery HD. The Recovery Disk Assistant uses a cloning process to create copies of the Recovery HD.
If your OS X installation wasn't able to create the Recovery HD, the OS X Recovery Disk Assistant won't be usable. To find out whether you have a Recovery HD, restart your Mac while holding down the option key. This will force your Mac to start using the startup manager, which will display all bootable volumes connected to your Mac. You can then pick the recovery volume, usually named Recovery HD. Once you select the recovery volume, your Mac should start up and display the recovery options. If all is well, go ahead and restart your Mac normally. If you don't have a recovery volume, you won't be able to use the Lion Recovery Disk Assistant.
An external drive to serve as the destination for the new Recovery HD. The external can be any drive that is bootable, including external USB, FireWire, and Thunderbolt-based drives, as well as most USB flash drives.
Finally, your external drive needs to have at least 650 MB of available space. One important note: The Recovery Disk Assistant will erase the external drive and then create only a 650 MB space for itself, which is pretty wasteful.
In our instructions, we'll partition the external into multiple volumes, so you can dedicate one volume to the Recovery HD, and save the rest of your external drive to use as you see fit.
Have everything you need? Then let's get going.
The OS X Recovery Disk Assistant will completely erase the target external volume. This means that if you use, say, a 320 GB hard drive that is partitioned as a single volume, then everything currently on that drive will be erased, and the Recovery Disk Assistant will create a new single partition that is only 650 MB, leaving the rest of the drive unusable. That's a pretty big waste of a perfectly good hard drive.
Luckily, you can fix this issue by first partitioning the external drive into at least two volumes. One of the volumes should be as small as you can make it, but larger than 650 MB. The remaining volume or volumes can be any size you wish to take up the rest of the available space. If your external drive contains data you wish to keep, be sure to read the following article:
Disk Utility - Add, Delete, and Resize Existing Volumes With Disk Utility
The above article provides detailed instructions on how to add and resize existing partitions on a hard drive without losing any existing data.
If you're willing to simply erase everything on the external drive, you can use the instructions in this article:
Partition Your Mac's Hard Drive With Disk Utility
Regardless of which method you use, you should end up with an external drive that has at least two volumes; one small volume for the recovery volume, and one or more larger volumes for your own general use.
One more thing: Be sure to note the name you give to the smaller volume you create, the one you will use for the recovery volume.
The OS X Recovery Disk Assistant display volumes by name, with no indication of size, so you need to know the name of the volume you wish to use, so you don't erase and use the wrong volume by mistake.
With everything prepped, it's time to use the OS X Recovery Disk Assistant to create the Recovery HD.
- Make sure your external drive is attached to your Mac, and that it shows as mounted on the desktop or in a Finder window.
- Mount the OS X Recovery Disk Assistant disk image you downloaded from the Apple web site by double-clicking its icon. (If you haven't yet downloaded the application, you can find a link to it on Page 2 of this guide). It will probably be in your Downloads directory; look for a file called RecoveryDiskAssistant.dmg.
- Open the OS X Recovery Disk Assistant volume you just mounted, and launch the Recovery Disk Assistant application.
- Because the application was downloaded from the web, you will be asked if you really want to open this application. Click Open.
- The OS X Recovery Disk Assistant license will display. Click the Agree button to continue.
- The OS X Recovery Disk Assistant will display all external volumes connected to your Mac. Click the volume you wish to use as the destination for the recovery volume. Click Continue to start the creation process.
- You will need to provide an administrator account password. Supply the requested information, and click OK.
- The Recovery Disk Assistant will display the progress of the disk creation.
- Once the recovery volume is created, click the Quit button.
That's it; you now have a recovery volume on your external drive.
A few things to note: The recovery volume is hidden; you won't be able to see it mounted on your Mac's desktop. Additionally, the default installation of Disk Utility won't be able to show you the hidden recovery volume.
There is, however, a simple way to add the ability to view hidden volumes to Disk Utility by enabling its debug menu.
Enable Disk Utility's Debug Menu
You should test your new recovery volume to confirm that it's working. You can do this by restarting your Mac while holding down the option key. You should see your new Recovery HD as one of the startup options. Select the new Recovery HD and see if your Mac will successfully boot and display the recovery options. Once you're satisfied that the Recovery HD is working, you can restart your Mac normally.